CADET (through the Fr. from the Late Lat. capitettum, a diminutive of caput, head, through the Provençal form capdet), the head of an inferior branch of a family, a younger son; particularly a military term for an accepted candidate for a commission in the army or navy, who is undergoing training to become an officer. This latter use of the term arose in France, where it was applied to the younger sons of the noblesse who gained commissioned rank, not by serving in the ranks or by entering the écoles militaires, but by becoming attached to corps without pay but with certain privileges. "Cadet Corps," in the British service, are bodies of boys or youths organized, armed and trained on volunteer military lines. Derived from "cadet," through the Scots form "cadee," comes "caddie," a messenger-boy, and particularly one who carries clubs at golf, and also the slang word "cad," a vulgar, ill-bred person.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)